Double-encapsulated compositions containing volatile and/or labile components, and processes for preparation and use thereof

ABSTRACT

A spray-dried composition comprising a volatile and/or labile component in a carrier, is further encapsulated in an extruded glassy matrix comprising: 
     (a) from about 40 to about 80 percent by weight of a water-soluble, chemically-modified starch having a dextrose equivalent not greater than about 2; 
     (b) from about 10 to about 40 percent by weight of a maltodextrin having a dextrose equivalent in the range of from about 5 to about 15; 
     (c) from about 5 to about 20 percent by weight of corn syrup solids or a polydextrose having a dextrose equivalent in the range of from about 21 to about 42; and 
     (d) from about 5 to about 20 percent by weight of a mono- or disaccharide. 
     The resultant glassy matrices are useful for introducing and/or retaining and/or stabilizing the volatile and/or labile components in cooked and uncooked food products.

FIELD OF THE INVENTION

This invention relates to double-encapsulated compositions containingvolatile and/or labile components, and to processes for the preparationand use thereof. These double-encapsulated compositions are useful forincorporating, retaining and stabilizing the volatile and/or labilecomponents, especially flavoring agents, into cooked and uncooked foodproducts, especially baked goods.

BACKGROUND OF THE INVENTION

It has long been known to skilled persons in the food industry that thetaste and aroma of food products are greatly affected by volatilecomponents present in such products. For example, such components ascoffee aroma, esters, acetaldehyde, various essential oils, sulfurcompounds and flavorings such as vanilla, augment and enhance theperceived taste and smell of a variety of food products. Consequently,to ensure the production of food products which are of consistentquality and are attractive to consumers, it is necessary to ensure thateach batch of product contains a proper, predetermined amount of suchvolatile components.

However, because of the volatility of these components, it is not easyto ensure that the predetermined amount of each volatile component ispresent in the final product as it reaches the consumer. Losses ofvolatile components may occur during storage prior to incorporation ofthe component into the food product, during the mixing of the componentwith the other ingredients of the food product, during baking or othercooking of the food product, during the transportation and storageinvolved in bringing the product to the ultimate consumer, and in somecases during the final preparation of the food product by the consumer,for example by reheating or microwaving of the food product. The extentof many of these losses are difficult to control; for example, there maybe a considerable time period between the beginning and the end of theuse of a batch of volatile component in a plant, so some of the batchmay be in storage for far longer than another part of the same batch,while the period which elapses between the time a product leaves theplant and the time it reaches a consumer is out of the manufacturer'scontrol.

These variations in losses of volatile components from food products mayproduce undesirable variations in the taste and aroma of the products asperceived by the consumer. In addition, such losses of volatilecomponents increase the cost of the food product, since it is necessaryto increase the amount of the volatile component included in the foodproduct to compensate for the losses which occur, and many volatilecomponents (for example, vanilla and some essential oils) are expensive.

The problems associated with volatile components are also experiencedwith labile components used in foods; the term "labile" is used hereinto denote a material which, because of its interaction with materialspresent in the environment, gradually undergoes degeneration anddestruction during storage. An example of a labile component isacetaldehyde, which is slowly destroyed by atmospheric oxygen.

To reduce or eliminate the aforementioned problems associated withvolatile and/or labile components, attempts have been made toencapsulate such components in a matrix which reduces the volatilityand/or lability of the component. Frequently, the matrix used iscomposed of one or more carbohydrates.

U.S. Pat. No. 2,809,895, to Swisher describes a process forencapsulation of an essential oil, such as lemon, lime or grapefruitoils, in a matrix comprising corn syrups, antioxidant and a dispersingagent. The essential oil, antioxidant and dispersing agent are added tothe corn syrup, the resultant mixture is heated to 85°-125° C. andagitated or extruded to form an emulsion in pellet form, and theresultant particles are washed with an essential oil solvent and driedunder vacuum to remove the solvent.

U.S. Pat. Nos. 2,856,291 and 2,857,281, both to Schultz, describe aprocess for the encapsulation of flavorants (for example, citrus oils)in a sugar base comprising sucrose, corn syrup and water. A hot emulsionof the flavorant is formed in the sugar base, and this emulsion isextruded as a stream or as globules, cooled to a plastic condition andcut into rods.

U.S. Pat. No. 2,919,989, also to Schultz, describes a modification ofthe process of the aforementioned U.S. Pat. No. 2,856,291 in which thesugar base used comprises, by weight, 15-40% sucrose, 10-15% lactose,5-14% maltose, 10-50% dextrose and not more than 15% dextrin.

U.S. Pat. No. 3,041,180 to Swisher describes an essential oil flavoringcomposition produced by mixing glycerol and 42 DE corn syrup solids intoan aqueous, semiplastic mass, which is then combined with the essentialoil by means of an emulsifier. The resulting mixture is extruded into acold solvent to form an extruded solid in which the essential oil isencapsulated by the glycerol and corn syrup solids. This extruded solidis then dried and an anti-caking agent added to produce an extrudedparticulate solid having an extended shelf life.

U.S. Pat. No. 3,314,803 to Dame et al. describes a method for fixing avolatile flavor such as acetaldehyde in a mannitol substrate. Theacetaldehyde is fixed in mannitol by first forming a solution ofmannitol and water, preferably a supersaturated solution of mannitol ofbetween 25-45% by weight. The supersaturated solution is formed byheating with agitation 2 to 10 parts by weight of mannitol with 10 partsby weight of water at 180°-212° F. until all of the mannitol isdissolved in the water and no mannitol crystals remain in the solution.The solution is then cooled while acetaldehyde is added thereto. Acontrolled reflux admixes the volatile and the solution is thenspray-dried.

U.S. Pat. No. 3,554,768 to Feldman describes a method for fixingacetaldehyde in selected carbohydrates; in this method, the acetaldehydeand the carbohydrate are uniformly mixed in water and the resultantmixture is dried to form a flavor-enhancing composition.

U.S. Pat. No. 3,704,137 to Beck describes an essential oil compositionformed by mixing oil with an antioxidant, separately mixing water,sucrose and hydrolyzed cereal solids (dextrose equivalent (DE)substantially below 20, and preferably between 10 and 15), emulsifyingthe two mixtures together, extruding the resultant mixture in the formof rods into a solvent, removing excess solvent and finally adding ananti-caking agent, preferably silica.

U.S. Pat. No. 3,971,852 to Brenner describes a process for encapsulatingan oil in a matrix comprising a polysaccharide (which may be dextrinizedstarch or hydrolyzed starch having a DE of 10-25) and a polyhydroxymaterial, which can be glucose, maltose or fructose. The ingredients areemulsified and spray dried.

U.S. Pat. No. 4,532,145 to Saleeb describes a process for fixingvolatile components in an amorphous substrate to produce amoisture-stable product. In this process, a low (90-500) molecularweight water-soluble material, such as a monosaccharide or disaccharide,having a melting point of from 80° to 180° C., is mixed with a high(1000-6000) molecular weight water-soluble polymeric material, such as apolysaccharide, in an aqueous solution. A volatile flavorant, such asacetaldehyde, is added to this solution, and the resultant mixture isspray-dried at a temperature of from 100° to 180° C. at the inlet andfrom 50° to 80° C. at the outlet.

U.S. Pat. No. 4,820,534 to Saleeb et al. describes a method for fixingvolatile flavorants in an extruded glass substrate which uses a matrixgenerally similar to that of U.S. Pat. No. 4,532,145 described above,but in which the mixture of flavorant and carbohydrates is heated abovethe glass transition temperature of the substrate and at or just abovethe melting point of the minor ingredient (the monosaccharide ordisaccharide) so that the minor ingredient melts and the majoringredient (the polysaccharide) dissolves in the minor ingredient toform a molten mass, and this molten mass is extruded to produce anamorphous, homogeneous, single-phase glass containing entrapped volatileflavorant, this glass having a glass transition temperature aboveambient temperature.

U.S. Pat. Nos. 4,610,890 and 4,707,367, both to Miller, describe aprocess for preparing a solid essential oil composition having a highcontent of the essential oil. This composition is prepared by forming anaqueous solution containing a sugar, a starch hydrolyzate and anemulsifier. The essential oil is blended with this aqueous solution in aclosed vessel under controlled pressure conditions to form a homogeneousmelt, which is then extruded into a relatively cold solvent, dried andcombined with an anti-caking agent.

U.S. Pat. No. 4,689,235 to Barnes describes a process which involvesgenerally the same steps as in the aforementioned U.S. Pat. No.4,610,890 but in which the solution used for encapsulation comprises amixture of a maltodextrin and hydrogen octenyl butanedioate.

One of the problems in such prior art methods for the encapsulation ofvolatile and/or labile components in carbohydrate matrices is thedifficulty of securing a sufficiently high glass transition temperaturefor the glassy matrices. Although the glassy carbohydrate matrices donot have a sharp melting point characteristic of crystalline solids,they do have a glass transition temperature (also known as softeningtemperature), which is the temperature at which the amorphous solidmatrix softens and becomes a viscous liquid.

When a glassy matrix containing an encapsulated volatile component isheated above its glass transition temperature, the encapsulated materialis released by diffusion at a rate which increases with increase oftemperature above the glass transition temperature. Even below the glasstransition temperature, the stability of the matrix increases (and thusthe loss of volatile component decreases) with the difference betweenthe temperature of the matrix and its glass transition temperature.Thus, it is desirable to use a matrix material having a glass transitiontemperature well above the temperature at which the encapsulatedmaterial will be stored and used.

Another problem in such prior art methods for the encapsulation ofvolatile and/or labile components in carbohydrate matrices is thehygroscopic nature of the matrices produced. Since the glassy matricesare plasticized and solubilized by water as well as softened by heat, itis important that the matrix not come into contact with water, whichwould permit escape of the volatile component from the matrix. Thehygroscopic nature of some prior art matrices requires specialprecautions to prevent plasticization of the matrix by atmosphericmoisture; since, under industrial conditions, it is usually impossibleto keep the matrices under completely anhydrous conditions, many priorart compositions require the use of anti-caking agents to prevent cakingcaused by plasticization of the matrix by moisture adsorbed from theair.

Flavoring compositions comprising a flavoring agent such as a liquidvanilla flavor encapsulated by spray-drying with a maltodextrin carrierare commercially available and are used for introducing the flavoringagent into foodstuffs. In addition to the aforementioned problems, ithas been found that these encapsulated products are less effective thanis desirable in preventing loss of the volatile flavorant when used infoodstuffs such as cookies, which require addition of the spray-driedcompositions to a dough which is subject to extensive manipulationbefore the production of the final cookie. It appears that the walls ofthe microcapsules in the spray-dried encapsulated products are sofragile that they rupture easily during manipulation of the dough, andthe flavoring agent released by the ruptured microcapsules can then actlike an unencapsulated flavoring agent, with resultant loss of flavoringagent, etc.

It has now been found that the problems associated with the use ofspray-dried encapsulated flavoring compositions in cookies and otherfoodstuffs can be eliminated, or at least significantly reduced, by afurther encapsulation of the flavoring composition in a glassy matrixwhich has a high glass transition temperature and which is sufficientlynon-hygroscopic that anti-caking agents are not normally required to beused.

SUMMARY OF THE INVENTION

This invention provides a process for encapsulation of a spray-driedsolid composition comprising at least one volatile and/or labilecomponent in a carrier, which process comprises forming a mixture of thecomposition with:

(a) from about 40 to about 80 percent by weight of a water-soluble,chemically-modified starch having a dextrose equivalent not greater thanabout 2;

(b) from about 10 to about 40 percent by weight of a maltodextrin havinga dextrose equivalent in the range of from about 5 to about 15;

(c) from about 5 to about 20 percent by weight of corn syrup solids or apolydextrose having a dextrose equivalent in the range of from about 21to about 42; and

(d) from about 5 to about 20 percent by weight of a mono- ordisaccharide,

all of said percentages being based upon the total weight of thecomponents (a), (b), (c) and (d);

and extruding the mixture to form a glassy matrix wherein the volatileand/or labile component is encapsulated.

In a preferred embodiment of this process:

component (a) comprises from about 50 to about 70 percent by weight ofthe mixture and is a succinyl starch derivative;

component (b) comprises from about 15 to about 30 percent by weight ofthe mixture and is a maltodextrin having a dextrose equivalent in therange of from about 8 to about 12;

component (c) comprises from about 7 to about 15 percent by weight ofthe mixture and is corn syrup solids having a dextrose equivalent in therange of from about 21 to about 30;

component (d) comprises from about 7 to about 15 percent by weight ofthe mixture and is a disaccharide;

the at least one volatile and/or labile component is present in themixture in an amount of from about 2 to about 15 percent by weight ofthe total weight of components (a), (b), (c) and (d); and

the glassy matrix formed has a glass transition temperature of at leastabout 40° C.

This invention also provides a glassy matrix comprising:

(a) from about 40 to about 80 percent by weight of a water-soluble,chemically-modified starch having a dextrose equivalent not greater thanabout 2;

(b) from about 10 to about 40 percent by weight of a maltodextrin havinga dextrose equivalent in the range of from about 5 to about 15;

(c) from about 5 to about 20 percent by weight of corn syrup solids or apolydextrose having a dextrose equivalent in the range of from about 21to about 42;

(d) from about 5 to about 20 percent by weight of a mono ordisaccharide; and

(e) a spray-dried composition containing at least one volatile and/orlabile component in a carrier,

all of these percentages being based upon the total weight of thecomponents (a), (b), (c) and (d).

Finally, this invention provides a process for incorporation of aspray-dried composition comprising at least one volatile and/or labilecomponent in a carrier into a cooked food product, which processcomprises:

forming a mixture of a spray-dried composition containing the at leastone volatile and/or labile component with:

(a) from about 40 to about 80 percent by weight of a water-soluble,chemically-modified starch having a dextrose equivalent not greater thanabout 2;

(b) from about 10 to about 40 percent by weight of a maltodextrin havinga dextrose equivalent in the range of from about 5 to about 15;

(c) from about 5 to about 20 percent by weight of corn syrup solids or apolydextrose having a dextrose equivalent in the range of from about 21to about 42; and

(d) from about 5 to about 20 percent by weight of a mono- ordisaccharide,

all of these percentages being based upon the total weight of thecomponents (a), (b), (c) and (d);

extruding the mixture to form a glassy matrix wherein the spray-driedcomposition containing at least one volatile and/or labile component isencapsulated;

adding the glassy matrix to the remaining ingredients of the foodproduct; and

cooking the resultant mixture to form the cooked food product.

BRIEF DESCRIPTION OF THE DRAWING

The sole FIGURE of the accompanying drawing is a graph showing therelationship between glass transition temperature and number averagemolecular weight for various carbohydrates.

DETAILED DESCRIPTION OF THE INVENTION

As already stated, in the process of the present invention, aspray-dried composition comprising at least one volatile component in acarrier (typically a carbohydrate or gum carrier), and in the form of anamorphous powder, is further encapsulated in a glassy matrix formed froma mixture of four different carbohydrates.

The first of these carbohydrates, which comprises from about 40 to about80, and preferably about 50 to about 70, percent by weight of themixture, is a water-soluble, chemically-modified starch having adextrose equivalent (DE) below about 2. Preferred starch derivatives aresuccinyl starch derivatives, the derivatives of starch with octenylsuccinate being especially preferred. Desirably, the starch derivativehas a dextrose equivalent in the range of about 0.5 to about 1.5. Starchderivatives suitable for use in the present process are readilyavailable commercially; one specific commercial product which has beenfound to give good results in the present process is that sold asAmiogum 23 by American Maize-Products Co., Hammond, Ind. (Neither themolecular weight nor the dextrose equivalent of this material isspecified by the manufacturer. However, using routine methods fordetermination of molecular weight of carbohydrates which will befamiliar to those skilled in the art, it has been found that M_(n), thenumber average molecular weight of this material is approximately18,000, which corresponds to a DE of 1, since DE=18016/M_(n).) Thestarch derivative used must be water-soluble; natural starches areinsufficiently soluble for use in the process of the present inventionand do not produce a satisfactory glassy matrix which will dissolverapidly in the mouth of the consumer (see below) to give quick releaseof the volatile and/or labile component.

The second of these carbohydrates, which comprises from about 10 toabout 40, and preferably about 15 to about 30, percent by weight of themixture, is a maltodextrin having a dextrose equivalent (DE) in therange of about 5 to about 15. Preferred maltodextrins are those having aDE in the range of about 8 to about 12. As those skilled in the foodindustry are well aware, a variety of maltodextrins meeting theserequirements are readily available commercially; one specificmaltodextrin which has been found to give good results in the presentprocess is that sold as Lodex 10 by American Maize-Products Co.,Hammond, Ind. This material has a DE of 10, corresponding to a numberaverage molecular weight of approximately 1800.

The third of these carbohydrates, which comprises from about 5 to about20, and preferably about 7 to about 15, percent by weight of themixture, is corn syrup solids or a polydextrose having a dextroseequivalent in the range of about 21 to about 42. Preferred corn syrupsolids are those having a DE in the range of about 21 to about 30.Again, it is well known that corn syrup solids meeting theserequirements are readily available commercially; one specific corn syrupsolids which has been found to give good results in the present processis that sold as Star-Dri 24 by A. E. Staley Manufacturing Co., Decatur,Ill. This material has a DE of 24, corresponding to a number averagemolecular weight of approximately 750.

The term "corn syrup solids" is conventionally used to denote themixture of carbohydrates produced by hydrolysis of corn starch andhaving dextrose equivalents in the range of 21 to 42. However, althoughsuch carbohydrates are usually produced by hydrolysis of high molecularweight starch, any carbohydrates having the required dextroseequivalents may be employed in the matrices of the present invention. Inparticular, such carbohydrates may be produced by polymerization oflower molecular weight carbohydrates rather than hydrolysis of highmolecular weight starches. "Polydextrose", produced commercially bePfizer, is the trade name for a glucose oligomer having a glasstransition temperature comparable to that of medium dextrose equivalentcorn syrup solids, and such polydextrose may be employed in place ofcorn syrup solids in the present matrices.

The fourth and last of these carbohydrates, which comprises from about 5to about 20, and preferably about 7 to about 15, percent by weight ofthe mixture, is a mono- or disaccharide. This carbohydrate may be, forexample, sucrose, glucose, lactose, fructose or maltose. In general,disaccharides are preferred over monosaccharides because the highermolecular weight of the disaccharides gives them a higher glasstransition temperature and a lower hygroscopicity. Among thedisaccharides, maltose is preferred over sucrose, because maltose, asthe crystalline monohydrate, melts in an extruder at a much lowertemperature than does sucrose.

The spray-dried encapsulated composition which is further encapsulatedby the process of the present invention may be any spray-driedcomposition comprising a volatile and/or labile component, provided thatthe spray-dried composition has a sufficiently small particle size to beencapsulated by the process of the present invention. The carrier of thespray-dried composition may be, for example, a dextrin, a maltodextrin,a cyclodextrin, a sugar, a protein, a gum, such a gum arabic, or anycombination thereof.

It has previously been shown (see Levine and Slade, A PolymerPhysico-Chemical Approach to the Study of Commercial Starch HydrolysisProducts (SHPs), Carbohydrate Polymers, 6, 213-344 (1986)) that thecharacteristic sub-zero glass transition temperature, T'_(g), of amaximally freeze-concentrated aqueous solution of a carbohydrate ormixture of carbohydrates shows an inverse linear correlation with thedextrose equivalent of the carbohydrate over a DE range of 0.3 to 100;in experiments reported in this paper, the coefficient of correlationbetween T'_(g) and DE was -0.98, in effect indicating that virtually allthe variation in T'_(g) was due to variation in DE. The accompanyingdrawing, which is a modified reproduction of one of the Figures fromthis paper, shows the variation of T'_(g) with number average molecularweight and DE of the carbohydrates. A similar relationship exists forvariation of T_(g), the conventional glass transition temperature, withnumber average molecular weight. Although the mixtures of carbohydratesused in the process of the present invention are more complex than thosetested in the aforementioned paper, it has been found that they displaythe same correlation between glass transition temperature and numberaverage molecular weight. Consequently, it is possible to calculate,with a high degree of accuracy, the glass transition temperature of theglassy matrix produced from any given carbohydrate mixture by theprocess of the present invention by calculating the number averagemolecular weight of the mixture (provided that due allowance is made forthe water content of the mixture, as discussed in more detail below).

It should be noted that one reason for the higher glass transitiontemperatures of the matrices of the present invention, as compared withthe prior art matrices discussed above, is the high proportion ofmodified starch used in the present matrices, and the increased numberaverage molecular weight of the matrix that this high proportion ofstarch provides. Although water-soluble, chemically-modified starcheshave been used in prior art glassy matrices, such starches havetypically been used in amounts of 20 percent by weight of thematrix-forming ingredients, in contrast to the 40 to 80 percent byweight of the components used in the matrices of the present invention.

The glass transition temperature of the matrices of the presentinvention declines sharply with increasing water content in the matrix.Accordingly, the water content of the matrix should be kept as low aspossible. However, the extrudability of the mixture of carbohydratesused to form the matrix declines with decreasing water content, and ifthe water content of the mixture is too low, the extruder may clog orgenerate heat sufficient to cause undesirable changes in the matrixformed. Accordingly, the optimum water content for extrusion of anyparticular mixture is a compromise between the glass transitiontemperature of the matrix to be produced and the extrudability of themixture. The optimum water content for any specific mixture can readilybe determined by routine empirical tests, which will be familiar tothose skilled in carbohydrate chemistry. In general, however, it hasbeen found that if the moisture content of the carbohydrate mixture(including the moisture which is inevitably present in carbohydrateseither as water of crystallization or as otherwise adsorbed water), asdetermined by overnight drying in an oven at 70° C., falls below about9-10 percent by weight, extrusion of the mixture tends to becomedifficult or impossible. If the carbohydrate components of the matrixare used in a "dry" state, i.e. with no apparent moisture present on thecarbohydrate, each carbohydrate will usually contain about 5-10 percentby weight of water. Accordingly, it is usually necessary to add somewater to the carbohydrate mixture to assist in the extrusion of thematrix; the amount of water is usually preferred to be within the rangeof from about 2 to about 7 percent by weight based upon the total weightof said components (a), (b), (c) and (d). Desirably, the moisturecontent of the final glassy matrix is in the range of from about 5 toabout 11 percent by weight.

The particle size of the various carbohydrates used to form the glassymatrices does not appear to be critical; use of the normal commercialforms of the various carbohydrates has been found to give satisfactoryresults, and maltose may conveniently be used in the form of themonohydrate. However, care should of course be taken to ensure that theingredients do not contain particles so large as to introducesignificant heterogeneities into the glassy matrix; accordingly, it maybe desirable to sieve the various ingredients before they are mixed.

To form the mixture of ingredients which will be extruded to form theglassy matrix, no special mixing techniques are required; the variousingredients are simply added to a mixer (for example, a Hobart mixer),and mixed gently until a homogeneous mixture is obtained. Care should betaken to ensure gentle mixing, since excessive shear strains andresultant fracture of the fragile walls of the microcapsules of thespray-dried encapsulated composition should be avoided as far aspossible. In general, it is not necessary to add any drying agents tothe mixture.

When the addition of water is needed for proper extrusion of themixture, this water is conveniently added directly to the extruder, in amanner which will be familiar to those skilled in extruder technology.However, if desired, the water may be added to the carbohydrate mixturebefore extrusion.

The extrusion of the dry mixture to form the glassy matrix requiresclose control because of the inherent difficulty of extruding a powderedcomposition. As already stated, in many cases it may be desirable to adda limited amount of water during extrusion, provided too high a moisturecontent in the final glassy matrix is avoided. Both single and twinscrew extruders may be used, but the screw speed should be carefullyregulated to prevent the development of excessive pressures andtemperatures which might produce an unsatisfactory matrix; the necessaryadjustments can easily be made empirically by persons skilled in theoperation of extruders. Generally, extruder temperatures should liewithin the range of about 35° to about 150° C., since exposure to highertemperatures tends to produce undesirable damage to the carbohydratesand a less satisfactory matrix. It has been found desirable to useextruders which are capable of providing multiple zones with differingtemperatures; in a preferred embodiment of the invention, the first ofthe temperature zones, adjacent the input of the extruder, has atemperature in the range of from about 35° to about 50° C. and the lastof the temperature zones, from which the extrudate leaves the extruder,has a temperature in the range of from about 80° to about 125° C.

The present glassy matrices are produced by extrusion rather than byspray-drying, because it has been found that the thermal stability ofthe extruded products produced from any given carbohydrate mixture ismuch greater than that of the corresponding spray dried product.

The physical dimensions of the extrudate are not critical, and may varydepending upon its intended use. However, when the extrudate contains aflavoring material intended for use in foodstuffs, it has been foundconvenient to produce the extrudate in the form of narrow rods having adiameter in the range of 0.3 to 3 mm., and desirably about 1 mm.Furthermore, in order to produce a uniform flavor throughout thefoodstuff, it is desirable to grind the extrudate, generally to below 40U.S. mesh.

The encapsulated volatile and/or labile components produced by theprocess of the present invention can be used in any application wherethe unencapsulated components have hitherto been used. However, theencapsulated components are especially useful for introducing, retainingand stabilizing flavoring materials in foodstuffs. The encapsulatecomponents are released very slowly, if at all, from the glassy matrixwhile the foodstuff is being stored at temperatures close to roomtemperature. However, when a consumer bites into the flavored foodstuff,the glassy matrix is plasticized or dissolved immediately by the waterpresent in the consumer's mouth, with consequent immediate release ofthe flavoring components. Thus, the flavoring components are releasedonly at the time they are needed for full flavor impact. This enablesone either to produce an improved flavor impact using the same amount offlavoring components, or to reduce the amount of flavoring components(many of which are expensive) while still producing the same flavorimpact in the foodstuff.

The encapsulated volatile and/or labile components produced by theprocess of the present invention can be used, and indeed are especiallyintended for use, in foodstuffs which are subjected to cooking,including baking; the encapsulated components can, however, also be usedin uncooked foodstuffs. Although the glassy matrix will normally besubjected to temperatures above its glass transition temperature duringthe cooking of the foodstuff, and will thus be at least partiallyliquified, it has been found that in practice such cooking does notresult in major loss of the volatile and/or labile components. This maybe attributed to the fact that, when the glassy matrices produced by thepresent process are heated above their glass transition temperatures,the liquid produced is highly viscous and viscoelastic ("rubbery"), incontrast to the low viscosity, non-viscoelastic liquids produced bymatrices formed from low molecular weight saccharides (e.g., sucroseglasses). The high viscosity and viscoelasticity of the liquified matrixis due to the high proportion of modified starch therein. Because of itshigh molecular weight and long chain length, the modified starchundergoes intermolecular entanglement in the molten mixture. Theentanglement persists in the glassy matrix formed below the glasstransition temperature (so reducing diffusion of the encapsulatedcomponent out of the glassy matrix during storage of the matrix belowits glass transition temperature) and in the viscoelastic liquid formedabove the glass transition temperature, and causes the rubbery characterand reduced diffusivity of the viscoelastic liquid formed above theglass transition temperature.

The high viscosity and viscoelasticity of the liquified matrix hindersdiffusion of the volatile and/or labile components out of the rubberyliquid. Furthermore, it is believed (although the invention is in no waylimited by this belief) that the lower molecular weight carbohydrates inthe glasses and rubbery liquids produced from the present matrices (i.e,the mono- and/or disaccharides and the corn syrup solids) in effect plugthe molecular-level voids or holes between the long, entangled chains ofthe starch derivative, thereby further hindering diffusion of thevolatile and/or labile components out of the glass or rubbery liquid.Certainly, diffusion of the volatile and/or labile components out of theliquids produced from the present glassy matrices is slower than from amatrix comprising only modified starch.

In general, it is not necessary to take any special precautions whenusing the encapsulated compositions of the present invention; thesecompositions are employed in exactly the same manner as the spray-driedencapsulated volatile and/or labile components which they contain,although of course due regard must be had to changes in the physicalform of the compositions. For example, when an encapsulated compositionof the present invention is to be used in a baked good, it is usuallyonly necessary to add the composition to the other ingredients of thedough or batter used to prepare the baked good.

The present process may be employed for encapsulation of a wide varietyof already-encapsulated volatile and/or labile components. Examples ofsuch components include flavoring components such as vanilla, vanillin,orange, chocolate, coffee, cocoa and butter flavorings and instant tea.The process can also be used to encapsulate aromatic materials, boththose which convey desirable aroma (for example cinnamon) and thosewhich have an undesirable odor which it is desired to mask, for examplefish oils. The process can also be used to encapsulate coloringmaterials, especially food colors, and other materials which are subjectto degradation during normal storage, for example vitamins (some ofwhich are subject to atmospheric oxidation) and leavening agents (whichmay react prematurely); thus, for example, the present invention may beemployed to encapsulate vitamins used to fortify various foodstuffs. Theencapsulated compositions of the invention may be employed, inter alia,in puddings, desserts, cakes, cookies and butter substitutes. Theencapsulated compositions may also be employed in foodstuffs which arenot cooked prior to consumption, for example chewing gum and coldbreakfast cereals.

The following Examples are given, though by way of illustration only, toshow details of compositions, methods and techniques used in the processof the present invention. Unless otherwise stated, all parts are byweight.

EXAMPLE 1

This Example illustrates the encapsulation of a spray-dried encapsulated"butter vanilla" flavor by the process of the present invention, and theuse of the resultant double-encapsulated flavor in the preparation of abutter vanilla cookie.

The ingredients used to prepare a glassy matrix of the invention were asfollows:

    ______________________________________                                        Ingredients          Parts by weight                                          ______________________________________                                        Succinyl modified starch                                                                           15.0                                                     Maltodextrin (DE 10) 5.0                                                      Corn syrup solids (DE 24)                                                                          2.5                                                      Maltose monohydrate (DE 50)                                                                        2.5                                                      Encapsulated butter vanilla flavor                                                                 0.82                                                     TOTAL                25.82                                                    ______________________________________                                    

All of the above ingredients were placed in a Hobart mixing bowl andmixed with a paddle for 30 minutes at low speed. The resultanthomogeneous mixture was found not to suffer from bridging problems whenfed to the hopper of an extruder, and consequently there was no need toadd any drying or anti-caking agents to the mixture.

The mixture was then extruded using a commercial twin-screw extruderhaving five temperature zones set to temperatures of 40°, 91°, 120°,101° and 102° C. respectively from the inlet to the outlet of theextruder. Water was fed to the extruder at a rate of less than 0.05parts by weight per part by weight of the dry mixture, and the die usedcontained 20 circular apertures each 1 mm. in diameter. This extrusionproduced an amorphous "melt" at a temperature of 102° C. at its exitfrom the extruder. This amorphous melt had a glass transitiontemperature of approximately 50° C. The product became a glass (i.e., acompletely amorphous solid) upon cooling to room temperature, as shownby its differential scanning calorimeter thermogram. The glassy matrixhad a moisture content of approximately 11 percent by weight, asmeasured by heating to 70° C. in a vacuum oven for 12 hours; this"moisture content" measurement of course overstates the actual moisturecontent of the extrudate, since it includes loss of the volatile flavorcomponents. The glassy matrix was then ground and passed through a 40U.S. mesh sieve.

The glassy matrix thus produced was used in the preparation of buttervanilla cookies. The ingredients used to prepare the cookies were asfollows:

    ______________________________________                                        Ingredients       Parts by weight                                             ______________________________________                                        Flour             300                                                         Sugar             132                                                         Butter and shortening                                                                           150                                                         Non-fat dry milk  9                                                           High fructose corn syrup                                                                        15                                                          Minor ingredients (salt,                                                                        15.16                                                       sodium bicarbonate,                                                           calcium phosphate,                                                            ammonium bicarbonate,                                                         dry eggs)                                                                     Water             45                                                          TOTAL             666.16                                                      ______________________________________                                    

Two separate batches of cookies were prepared, the batches differingonly in the flavoring used. The first batch was a control batch in whichthe flavoring was 0.40 parts by weight of a liquid, non-encapsulatedvanilla flavoring. In the second batch of cookies, the flavoring was15.68 parts by weight of the butter vanilla flavor-containing glassymatrix, which provided the same total weight of vanilla flavoring as inthe first (control) batch.

Both batches of cookies were prepared in the following manner. Thesugar, non-fat dry milk, salt, dry eggs, shortening and butter wereplaced in a Hobart mixer and mixed with a paddle at high speed. Theammonium bicarbonate was then added in solution in the water, togetherwith the high fructose corn syrup, and the resultant mixture mixed atmedium speed. The flavoring was then added; in the case of the firstbatch of cookies, in which only liquid flavoring was used, the mixturewas mixed for two minutes at high speed following addition of theflavoring, whereas in the other batch of cookies, in which the solidflavoring was used, the mixture was mixed for three minutes at highspeed. Finally, the flour and the calcium phosphate were added and themixture mixed at slow speed.

The dough thus produced was kneaded by hand and portions of 25 gramswere used to make each cookie. The cookies were baked for 9 to 10minutes at a temperature of 36° F.

Informal taste tests indicated that the cookies formulated with thedouble-encapsulated flavoring composition of the present invention had ataste at least as good as (i.e., stronger butter vanilla flavor than)that of the control cookies.

EXAMPLE 2

This Example illustrates the encapsulation of a spray-dried encapsulatedmustard flavor by the process of the present invention.

Example 1 was repeated except that the butter vanilla flavor wasreplaced by 2.8 parts by weight of a commercial spray-dried mustardspice mix, and that the temperature of that last zone of the extruder(nearest the outlet) was kept in the range of 90°-100° F. Thedouble-encapsulated composition was produced in the form of rods 1 mm.in diameter, which were then ground and passed through a 40 U.S. meshsieve to produce a pulverulent mustard spice flavor composition suitablefor use in flavoring a pretzel batter. The glassy extruded rods had a Tgof 52° C. and a moisture content of 8.2% by weight.

Processes and compositions generally similar to those of the presentinvention, but using as starting material pre-encapsulated volatileand/or labile components, are described and claimed in copending U.S.application Ser. No. 07/415,867, U.S. Pat. No. 5,009,900 by the presentinventors, filed Oct. 2, 1989, and entitled "Glassy Matrices ContainingVolatile and/or Labile Components, and Processes for Preparation and UseThereof."

What is claimed is:
 1. A process for encapsulation of a spray-driedcomposition comprising at least one volatile and/or labile component ina carrier, which process comprises forming a mixture of said compositionwith:(a) from about 40 to about 80 percent by weight of a water-soluble,chemically-modified starch having a dextrose equivalent not greater thanabout 2; (b) from about 10 to about 40 percent by weight of amaltodextrin having a dextrose equivalent in the range of from about 5to about 15; (c) from about 5 to about 20 percent by weight of cornsyrup solids or a polydextrose having a dextrose equivalent in the rangeof from about 21 to about 42; and (d) from about 5 to about 20 percentby weight of a mono-or disaccharide, all of said percentages being basedupon the total weight of said components (a), (b), (c) and (d); andextruding the mixture to form a glassy matrix having a glass transitiontemperature of at least 40° C. wherein the volatile and/or labilecomponent is encapsulated.
 2. A process according to claim 1 whereincomponent (a) is present in an amount of from about 50 to about 70percent by weight.
 3. A process according to claim 1 wherein component(a) is a succinyl starch derivative.
 4. A process according to claim 1wherein component (a) is a derivative of starch with octenyl succinate.5. A process according to claim 1 wherein component (a) has a dextroseequivalent in the range of about 0.5 to about 1.5.
 6. A processaccording to claim 1 wherein component (b) is present in an amount offrom about 15 to about 30 percent by weight.
 7. A process according toclaim 1 wherein component (b) has a dextrose equivalent in the range ofabout 8 to about
 12. 8. A process according to claim 1 wherein component(c) is present in an amount of from about 7 to about 15 percent byweight.
 9. A process according to claim 1 wherein component (c) has adextrose equivalent in the range of about 21 to about
 30. 10. A processaccording to claim 1 wherein component (d) is present in an amount offrom about 7 to about 15 percent by weight.
 11. A process according toclaim 1 wherein component (d) comprises a disaccharide.
 12. A processaccording to claim 11 wherein component (d) consists essentially ofmaltose.
 13. A process according to claim 1 wherein the compositioncontaining at least one volatile and/or labile component is a flavoringcomposition.
 14. A process according to claim 13 wherein the flavoringcomposition contains at least one of vanilla and vanillin.
 15. A processaccording to claim 1 wherein the composition containing at least onevolatile and/or labile component is added to the mixture in an amount offrom about 1 to about 20 percent by weight of the total weight ofcomponents (a), (b), (c) and (d).
 16. A process according to claim 15wherein the composition containing at least one volatile and/or labilecomponent is added to the mixture in an amount of from about 2 to about12 percent by weight of the total weight of components (a), (b), (c) and(d).
 17. A process according to claim 1 wherein said extrusion iseffected at a temperature in the range of from about 35° to about 150°C.
 18. A process according to claim 17 wherein said extrusion iseffected in an extruder having a plurality of zones held at differingtemperatures, the first of said zones having a temperature in the rangeof from about 35° to about 50° C. and the last of said zones, from whichthe extrudate leaves the extruder, having a temperature in the range offrom about 80° to about 125° C.
 19. A process according to claim 1wherein the mixture is extruded in the form of rods having a diameter inthe range of about 0.3 to about 3 mm.
 20. A process according to claim 1wherein water is included in said mixture prior to extrusion thereof.21. A process according to claim 20 wherein the quantity of waterincluded in said mixture is sufficient to produce a moisture content offrom about 5 to about 11 percent by weight in the final glassy matrix.22. A process according to claim 20 wherein the quantity of waterincluded in said mixture is from about 2 to about 7 percent by weightbased upon the total weight of said components (a), (b), (c) and (d).23. A process according to claim 1 wherein the extruded glassy matrix isthereafter incorporated into a dough or batter.
 24. A process accordingto claim 1 wherein the carrier of the spray-dried composition comprisesat least one of a carbohydrate, a protein, and a gum.
 25. A process forencapsulation of a spray-dried composition comprising at least onevolatile and/or labile component in a carbohydrate, protein, or gummatrix, which process comprises forming a mixture of said compositionwith:(a) from about 50 to about 70 percent by weight of a succinylstarch derivative having a dextrose equivalent not greater than about 2;(b) from about 15 to about 30 percent by weight of a maltodextrin havinga dextrose equivalent in the range of from about 8 to about 12; (c) fromabout 7 to about 15 percent by weight of corn syrup solids having adextrose equivalent in the range of from about 21 to about 30; and (d)from about 7 to about 15 percent by weight of a disaccharide, all ofsaid percentages being based upon the total weight of said components(a), (b), (c) and (d), the composition containing at least one volatileand/or labile component being present in the mixture in an amount offrom about 2 to about 12 percent by weight of the total weight ofcomponents (a), (b), (c) and (d), and extruding the mixture to form aglassy matrix having a glass transition temperature of at least about40° C. and wherein the composition containing at least one volatileand/or labile component is encapsulated.
 26. A glassy matrix produced bya process according to claim
 1. 27. A glassy matrix produced by aprocess according to claim
 25. 28. A glassy matrix comprising:(a) fromabout 40 to about 80 percent by weight of a water-soluble,chemically-modified starch having a dextrose equivalent not greater thanabout 2; (b) from about 10 to about 40 percent by weight of amaltodextrin having a dextrose equivalent in the range of from about 5to about 15; (c) from about 5 to about 20 percent by weight of cornsyrup solids or a polydextrose having a dextrose equivalent in the rangeof from about 21 to about 42; (d) from about 5 to about 20 percent byweight of a mono-or disaccharide; and (e) a spray-dried compositioncontaining at least one volatile and/or labile component in a carrier,all of said percentages being based upon the total weight of saidcomponents (a), (b), (c) and (d) and wherein said glassy matrix has aglass transition temperature of at least 40° C.
 29. A glassy matrixaccording to claim 28 wherein component (a) is present in an amount offrom about 50 to about 70 percent by weight.
 30. A glassy matrixaccording to claim 28 wherein component (a) is a succinyl starchderivative.
 31. A glassy matrix according to claim 28 wherein component(a) is a derivative of starch with octenyl succinate.
 32. A glassymatrix according to claim 28 wherein component (a) has a dextroseequivalent in the range of about 0.5 to about 1.5.
 33. A glassy matrixaccording to claim 28 wherein component (b) is present in an amount offrom about 15 to about 30 percent by weight.
 34. A glassy matrixaccording to claim 28 wherein component (b) has a dextrose equivalent inthe range of about 8 to about
 12. 35. A glassy matrix according to claim28 wherein component (c) is present in an amount of from about 7 toabout 15 percent by weight.
 36. A glassy matrix according to claim 28wherein component (c) has a dextrose equivalent in the range of about 21to about
 30. 37. A glassy matrix according to claim 28 wherein component(d) is present in an amount of from about 7 to about 15 percent byweight.
 38. A glassy matrix according to claim 28 wherein component (d)comprises a disaccharide.
 39. A glassy matrix according to claim 38wherein component (d) consists essentially of maltose.
 40. A glassymatrix according to claim 28 wherein the carrier of the spray-driedcomposition comprises at least one of a carbohydrate, a protein, and agum.
 41. A glassy matrix according to claim 28 wherein the carrier ofthe spray-dried composition comprises a maltodextrin.
 42. A glassymatrix according to claim 28 wherein the composition containing at leastone volatile and/or labile component is a flavoring composition.
 43. Aglassy matrix according to claim 42 wherein the flavoring compositioncontains at least one of vanilla and vanillin.
 44. A glassy matrixaccording to claim 28 wherein the composition containing at least onevolatile and/or labile component is present in the matrix in an amountof from about 1 to about 20 percent by weight of the total weight ofcomponents (a), (b), (c) and (d).
 45. A glassy matrix according to claim44 wherein the composition containing at least one volatile and/orlabile component is present in the matrix in an amount of from about 2to about 12 percent by weight of the total weight of components (a),(b), (c) and (d).
 46. A glassy matrix according to claim 28 in the formof rods having a diameter in the range of about 0.3 to about 3 mm.
 47. Aglassy matrix according to claim 28 having a moisture content of fromabout 5 to about 11 percent by weight.
 48. A glassy matrixcomprising:(a) from about 50 to about 70 percent by weight of a succinylstarch derivative having a dextrose equivalent not greater than about 2;(b) from about 15 to about 30 percent by weight of a maltodextrin havinga dextrose equivalent in the range of from about 8 to about 12; (c) fromabout 7 to about 15 percent by weight of corn syrup solids having adextrose equivalent in the range of from about 21 to about 30; (d) fromabout 7 to about 15 percent by weight of a disaccharide; and (e) fromabout 2 to about 12 percent by weight of a spray-dried compositioncomprising at least one volatile and/or labile component in acarbohydrate, protein, or gum carrier, said composition beingencapsulated within the glassy matrix, all of said percentages beingbased upon the total weight of said components (a), (b), (c) and (d) andwherein said glassy matrix has a glass transition temperature of atleast 40° C.
 49. A process for incorporation of a spray-driedcomposition comprising at least one volatile and/or labile component ina carrier into a cooked food product, which process comprises:forming amixture of a spray-dried composition containing the at least onevolatile and/or labile component with: (a) from about 40 to about 80percent by weight of a water-soluble, chemically-modified starch havinga dextrose equivalent not greater than about 2; (b) from about 10 toabout 40 percent by weight of a maltodextrin having a dextroseequivalent in the range of from about 5 to about 15; (c) from about 5 toabout 20 percent by weight of corn syrup solids or a polydextrose havinga dextrose equivalent in the range of from about 21 to about 42; and (d)from about 5 to about 20 percent by weight of a mono-or disaccharide,all of said percentages being based upon the total weight of saidcomponents (a), (b), (c) and (d); extruding the mixture to form a glassymatrix wherein the spray-dried composition containing at least onevolatile and/or labile component is encapsulated, and wherein saidglassy matrix has a glass transition temperature of at least about 40°C.; adding the glassy matrix to the remaining ingredients of the foodproduct; and cooking the resultant mixture to form the cooked foodproduct.
 50. A process according to claim 49 wherein the glassy matrixis added to the remaining ingredients while the ingredients are in theform of a dough or batter, and the dough or batter is thereafter bakedto form a baked food product.
 51. A process according to claim 49wherein the extruded glassy matrix is ground before being added to theremaining ingredients of the food product.
 52. A process according toclaim 49 wherein the volatile and/or labile component is a flavoringcomponent.
 53. A process according to claim 52 wherein the volatilecomponent comprises at least one of vanilla and vanillin.
 54. A processfor incorporation of a spray-dried composition containing at least onevolatile and/or labile component in a carbohydrate or gum carrier into abaked food product, which process comprises:forming a mixture of aspray-dried composition containing the at least one volatile and/orlabile component with: (a) from about 50 to about 70 percent by weightof a succinyl modified starch derivative having a dextrose equivalentnot greater than about 2; (b) from about 15 to about 30 percent byweight of a maltodextrin having a dextrose equivalent in the range offrom about 8 to about 12; (c) from about 7 to about 15 percent by weightof corn syrup solids having a dextrose equivalent in the range of fromabout 21 to about 30; and (d) from about 7 to about 15 percent by weightof a disaccharide, all of said percentages being based upon the totalweight of said components (a), (b), (c) and (d); extruding the mixtureto form a glassy matrix wherein the composition containing at least onevolatile and/or labile component is encapsulated, and wherein saidglassy matrix has a glass transition temperature of at least about 40°C.; adding the glassy matrix to a dough or batter containing theremaining ingredients of the food product; and baking the resultantmixture to form the baked food product.
 55. A cooked food productproduced by a process according to claim
 48. 56. A baked food productproduced by a process according to claim
 54. 57. A dough or battercontaining a glassy matrix according to claim 28.